SD/MMC cards, a year later

John Watlington wad at
Fri Aug 20 15:15:16 EDT 2010

On Aug 20, 2010, at 2:55 PM, Hal Murray wrote:

>> One frustration has been the rate of change in the SD industry. The dominant
>> model from a vendor in a particular size and speed may only be in production
>> for three or four months before being superseded.  Vendors are reluctant to
>> properly inform Quanta of changes which might require retesting.   The
>> result is that SD card certification is an ongoing process. 
> How many do I have to buy before a distributor or manufacturer will 
> cooperate?  Or how much extra does it cost to get them to cooperate?

It appears to be a matter of cost more than volume, although it can be
difficult to differentiate the two.

> Is that whole industry segment so focused on low-cost that nobody knows how 
> to keep track of what they manufacturer/deliver?

Some manufacturers track this relatively well (although it can be hard to
get them to communicate this information).   Others (whom we don't deal
with at all) seem to have little to no control.

> What do cell phone manufacturers do?

A number of them are paying a premium for eMMC chip from a single
manufacturer to get around this.

Others just accept that failures are going to happen.   Note that
almost all the SD cards I've tested would work fine for average
use.   In my testing, I'm expecting cards to survive a usage that is
equivalent to filling half the card with new data (2 GB) every day for
five years.

Both Apple and Microsoft are using raw NAND flash chips in
their products as a way of maintaining more control.

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